JPH0469948B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an electrophotographic photoreceptor.
Provided is a novel electrophotographic photoreceptor provided with a photosensitive layer containing a trisazo compound using 4''-triamino-benzyldiphenylamine as a diazo component. (Prior art and its problems) In recent years, electrophotographic methods have been Its use is not limited to the field of copying machines, but has also expanded to fields where photographic technology has traditionally been used, such as printing plates, slides, film, and microfilm, and is also being applied to high-speed printers that use lasers and CRTs as light sources. Therefore, the requirements for electrophotographic photoreceptors are becoming more sophisticated and wide-ranging. Until now, photoreceptors used in electrophotography have been made of inorganic materials such as amorphous selenium, cadmium sulfide, and zinc oxide. Most of them had a photosensitive layer made of a photoconductive substance as a main component.Although these photoreceptors made of inorganic substances are useful, they also have various drawbacks.In recent years, in order to compensate for this, Electrophotographic photoreceptors using various organic substances as photoconductive substances have been proposed.
It has begun to be put into practical use. Needless to say, the electrophotographic photoreceptor must have a carrier generation function and a carrier export function. Many pigments have been proposed as organic compounds that can be used as carrier generating substances, such as phthalocyanine, polycyclic quinone, indigo, dioxazine, quinacridone, and azo pigments, but only a limited number of them have been put into practical use. It is being In addition, the range of carrier transfer materials that can be selected is limited, so that at present no material that satisfactorily meets the wide range of requirements of electrophotographic processes has yet been obtained. (Means for Solving the Problems) As a result of intensive research to improve organic electrophotographic photoreceptors, the present inventors found that 4,4',4''--triamino-
The inventors have discovered that a photosensitive layer containing a trisazo compound using benzyldiphenylamine as a diazo component has excellent electrophotographic properties, leading to the present invention. That is, the present invention is an electrophotographic photoreceptor characterized in that a photosensitive layer containing a trisazo compound represented by the following general formula () is provided on a conductive support. However, A in the above formula is a general formula In the above formula, X represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted aromatic heterocyclic group. Specific examples of the compound represented by the general formula () include the following compounds. (Represented by the group X of A in the compound of general formula ()). No. 7) 2,3-diethoxy-4-phenylcarbamoylphenyl (8) 4-acetylaminophenyl (9) 2,4-dimethylphenyl (10) 2-methylphenyl (11) 2,5-dimethoxy-4 -Chlorphenyl (12) 3-nitrophenyl (13) 1-naphthyl (14) 5-methoxybenzothiazol-2-yl (15) 2-thiazolyl The electrophotographic photoreceptor of the present invention has the above general formula ()
By utilizing the excellent carrier generation function of the trisazo compound shown in the formula as a carrier generation material for so-called laminated or dispersion type electrophotographic photoreceptors, electrophotography with improved charging characteristics, charge retention, sensitivity, residual potential, etc. It is a photoreceptor that not only has excellent properties, but also has good coating physical properties, shows little deterioration due to repeated use, and exhibits stable performance without changing its properties even when exposed to heat, humidity, or light. The above compounds can be synthesized by known methods. First, 4,4',4''-triamino-benzyldiphenylamine is diazotized by a conventional method, and the resulting trisdiazonium salt is coupled with a coupling component to obtain a trisazo compound having a structure represented by the general formula (). One example of synthesis is given below, but other trisazo compounds having the structure represented by the general formula () can also be synthesized according to the synthesis example below. In the following synthesis examples, "part" or "%" each indicates parts by weight or % by weight. Synthesis example (for exemplified compound 1) 14.5 parts of 4,4′,4″-triamino-benzyldiphenylamine was dispersed in 300 parts of water and 63 parts of 35% concentrated hydrochloric acid, and this liquid was maintained at 0 to 5°C. While stirring well
115 parts of a 10% aqueous sodium nitrite solution was added dropwise over 10 minutes, and after the addition was complete, the mixture was stirred for an additional 15 minutes to obtain a diazonium salt solution. After dissolving 28.5 parts of acetoacetanilide in 1000 parts of aqueous sodium hydroxide solution, it was cooled and
The above diazonium salt solution was added dropwise over a period of 15 minutes while maintaining the temperature at °C. After the addition was completed, the mixture was stirred for an additional 2 hours, and the trisazo compound formed was filtered off and thoroughly washed to obtain 42.1 parts of a crude product of Exemplified Compound 1. This was washed successively with DMF, methanol, and then water, and dried to obtain a purified product. The physical configuration of the electrophotographic photoreceptor of the present invention may be in any known form. A carrier generating layer containing the above trisazo compound as a carrier generating substance as a main component and a carrier transporting layer containing a carrier transporting substance as a main component may be laminated on a conductive support, or a carrier generating substance may be used as a carrier. A photosensitive layer dispersed in the transport material may also be provided. Since these may be provided through an intermediate layer, the following patterns are possible. () Conductive support / carrier generation layer / carrier transport layer () conductive support / carrier transport layer / carrier transport layer () conductive support / carrier transport layer containing carrier generation substance () conductive support / Intermediate layer/carrier generation layer/
Carrier transport layer () Conductive support / Intermediate layer / Carrier transport layer /
Carrier generation layer () Conductive support/intermediate layer/carrier transport layer containing carrier generation substance The intermediate layer here refers to a barrier layer or an adhesive layer. It is also possible to provide a thin layer on the electrophotographic photoreceptor having the above structure for the purpose of surface protection or the like. Carrier transport materials include those that transport electrons and those that transport holes, and either can be used to form the electrophotographic photoreceptor of the present invention. The electrophotographic photoreceptor of the present invention can be manufactured in a conventional manner according to techniques known in the manufacture of electrophotographic photoreceptors using organic photoconductive materials. For example, to form a carrier generating layer that is a two-layer photosensitive layer, the above-mentioned trisazo compound is made into fine particles in a suitable medium, a binder is added as needed, and the carrier generation layer is formed directly on the conductive support or as an intermediate layer. or over a previously formed carrier transport layer and dry. The fine particles in the medium need to be dispersed with a diameter of 5 μm or less, preferably 3 μm, optimally 1 μm. When using a binder, it is preferably a film-forming polymer compound that is hydrophobic, has a high conductivity, and is electrically insulating, although there is no particular limitation. Various thermoplastic or thermosetting synthetic resins can be suitably used. As will be readily understood, it is advantageous for the medium to have the ability to dissolve the binder. The amount of binder used is selected from a range of 0.1 to 5 times the weight of the carrier generating substance. The thickness of the carrier generation layer is in the range of 0.01 to 20 μm. Preferably it is in the range of 0.05 to 20 μm.
Preferably it is 0.05 to 5 μm. The carrier transport layer can be formed by dispersing or dissolving a carrier transport substance in a suitable medium, coating the mixture, and drying the mixture.
It is preferred to use a binder, unless the carrier transport material is one that also acts as a binder itself, such as poly-N-vinylcarbazole or polyglycidylcarbazole. As the binder, the same type of binder as used for forming the carrier generation layer can be used. The amount of binder used is suitably 0.2 to 5 times the weight of the carrier transport material. The thickness of the carrier transport layer is in the range of 1 to 100 μm, preferably 5 to 50 μm. On the other hand, in order to form a dispersed carrier generation layer-carrier transport layer, a carrier transport substance is dissolved in the above-mentioned dispersion liquid for forming the carrier generation layer.
It may be applied onto a conductive support. Although the carrier transport material is optional, it is generally preferred to add a binder, except when using one that itself serves as a binder, as described above. When an intermediate layer is provided between the conductive support and the above laminated or dispersed photosensitive layer, the intermediate layer contains a carrier generating substance, a carrier transporting substance,
One type or a mixture of two or more types of binders, additives, etc., and commonly used materials can be used as long as the function as an intermediate layer is not impaired. The film thickness is
The thickness is preferably 10 μm or less, preferably 1 μm or less. Other known techniques can also be applied to the electrophotographic photoreceptor of the present invention. For example, the photosensitive layer may contain a sensitizer. Suitable sensitizers include Lewis acids and dyes that form charge transfer complexes with organic photoconductive substances. In addition, in order to improve film formability, flexibility, mechanical strength, etc. of the photosensitive layer, plasticizers, ultraviolet absorbers, antioxidants, etc.
Additives such as lubricants, adhesion promoters, and dispersants may be added, and carrier-generating substances and carrier-transporting substances may be added to the extent that they do not impair the characteristics of the electrophotographic photoreceptor aimed at in the present invention. In the present invention, ordinary coating methods can be used to form the carrier generation layer, carrier transport layer, intermediate layer or surface layer. As is clear from the following Examples, the electrophotographic photoreceptor of the present invention has excellent charging characteristics, sensitivity characteristics, and image forming properties, and has good photosensitivity. There is little variation in charging characteristics and little optical fatigue. It also has high weather resistance. Next, the present invention will be explained in more detail with reference to Examples. The word "part" in the text indicates parts by weight. Example 1 1 part of the above exemplary compound (1) and 1 part of polyester resin (Toyobo "Vylon 200") were mixed with tetrahydrofuran.
50 parts and sufficiently dispersed with a ball mill.The dispersion was applied onto an aluminum plate using a wire coater and dried with hot air at 120℃ for 30 minutes to determine the film thickness.
A carrier generation layer of 0.3 μm was provided. On top of that, apply a solution of 5 parts of P-diethylaminobenzaldehyde-N-phenyl-N-benzylhydrazone and 5 parts of polycarbonate resin (Teijin Kasei "Panlite L-1250") dissolved in 70 parts of 1,2-dichloroethane. Then, it was dried with hot air at 60°C for 3 hours to form a carrier transport layer with a thickness of 14 μm. The photosensitive plate manufactured in this way was heated at 25℃ and RH.
(Relative humidity) After leaving it in an atmosphere of 55% and adjusting the humidity, use an electrostatic paper tester (Kawaguchi Electric Manufacturing Co., Ltd. "SP-
428'') using the static method to charge the corona at a voltage of -6KV, and after keeping it in a dark place for 10 seconds, the sample surface illuminance was set to 5.0 using a tungsten lamp as the light source.
The electrophotographic properties were evaluated by exposing the film to light at a brightness of 100 lux, and the following results were obtained. Vo (initial charging voltage) = -860 (V) Vd10 (potential retention rate for 10 seconds in the dark) = 85.5 (%) E1/2 (half-attenuation exposure amount) = 2.5 (lux seconds) Example 2 The properties were measured in the same manner as in Example 1, except that Exemplary Compound (2) was used, and the results were as follows. Vo = -760 (V) Vd10 = 79.5 (%) E1/2 = 3.2 (lux / seconds) Example 3 1.5 parts of exemplified compound (3) and 1 part of polyester resin (Toyobo "Vylon 200") were mixed into 1, Pour into 250 parts of 2-dichloroethane and disperse with a ball mill.
The dispersion was applied onto a polyester film deposited with aluminum and dried with hot air at 120° C. for 30 minutes to form a carrier generation layer with a thickness of 0.5 μm. On top of that, 9-ethylcarbazole-3-carbaldehyde-1,1-diphenylhydrazone 10
Part and polyester resin (said "Byron 200" 10
100 parts of 1,2-dichloroethane was applied and dried with warm air at 60°C for 3 hours until the film thickness
A carrier transport layer of 15 μm was formed. The characteristics of this electrophotographic photoreceptor were measured and the following results were obtained. Vo = -640 (V) Vd10 = 88.0 (%) E1/2 = 2.0 (lux seconds) Examples 4 to 10 The following exemplified compound was used in place of exemplified compound (3) in Example 3, and the other A photoreceptor was manufactured in the same manner as in Example 3. The characteristics of each are as follows.

[Table] Example 11 The electrophotographic photoreceptor produced in Example 1 was charged and discharged 1000 times to examine changes in characteristics. The results are as follows, and it was found that the repeated stability was excellent.

[Table] Example 12 A 0.02 μm thick film made of vinyl chloride-vinyl acetate-maleic anhydride copolymer (Sekisui Scientific “Eslec MF-10”) was placed on an aluminum laminated polyester film (aluminum foil thickness 10 μm). A dispersion of 1 part of Exemplary Compound (2) dispersed in 50 parts of 1,4-dioxane using an attritor was applied on top of the intermediate layer, and the film was dried with hot air at 100°C for 30 minutes to determine the film thickness.
A carrier generation layer of 0.2 μm was provided. On top of that, 6 parts of 2,5-bis(4-N,N-diethylaminophenyl)-1,3,4-oxadiazole and 10 parts of polycarbonate resin (Mitsubishi Gas Science "Corpilon S=1000") were added in 1 part. , a solution dissolved in 100 parts of 2-dichloroethane was applied and heated at 60℃
It was dried with hot air for 3 hours to form a carrier generation layer with a thickness of 10 μm. When the E1/2 of the electrophotographic photoreceptor thus obtained was measured, it was 3.1 lux·sec. This electrophotographic photoreceptor was charged by -7KV corona discharge in a dark place, and imagewise exposed at a maximum light intensity of 30 lux seconds.
When developed using a magnetic brush method and transferred, a clear image with sufficient contrast and good gradation was obtained.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor characterized in that a photosensitive layer containing a trisazo compound represented by the following general formula () is provided on a conductive support. (However, A in the above formula is a general formula In the above formula, X represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted aromatic heterocyclic group. 2. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains a carrier generating substance and a carrier transporting substance, and the photosensitive layer is a trisazo compound represented by the above general formula ().